Mounting for aircraft components



June 8, 1943. P. w. BURKE 2,321,065 MOUNTING FOR AIRCRAFT COMPONENTS Filed Jan. 29, 1941 1? T" 1 -L f Q Q a a a 4 2a 24' /7 A /NVE/V7 O/ ,"Q,/"' 165 R136? W Patented June 8, 1943 2,321,055 I 'MOUNTING FOR AIRCRAFT coMPoNENTs Peter Walter Burke, -Cheltenham, England, assignor to Dowty Equipment Limited, Cheltenham, England Application January 29, 1941, Serial No. 377,397 r I In Great Britain February 1, 1940. r 7

12 Claims. (01. 244-102) The present invention is a retraction and extension arrangement for aircraft components and accessories in which energy available in retraction is stored in the retracted condition for use in extension. I

Although of more general application, the in vention has a particular embodiment in aircraft undercarriage gear. 7

It is an object of the invention to provide a retraction and extension scheme in various forms embodyingautomatic extensionmeans in a sim ple and practical manner.

Another object of the invention is to provide a retraction and extension scheme in which extension operation does not rely on operations? a fluid actuated jack or equivalent rernotely'controlled element, but rather is accomplished by a spring or the like which has been loadedduring retraction.

In the accompanying drawing, forming part of this specificatiom and in which like'reference numerals are employed to designate like parts throughout the same:

The jack is connected between the lug 8 on the end cap 9 of the pillar 3 and a fixed anchorage 4A. The end cap 9 carries a peg In which projects into a cam slot ll of a fixed guide plate I! (which may be duplicated in a lateral sense). A projection l3 on the end of the cap 9 co-opcrates with a fixed socket I4 to provide a down latch when the unit is fully extended as shown. The straight part at the upper end of the cam slot ll may also contribute to locking. Assuming the unit to be extended as shown in the drawing, and retraction is required, pressure is applied to the jack plunger through the pipe line i to retract the jack 5. During initial jack operatlon, the end cap 9 is drawn down against the loading spring I5. By the time the projection l3 has disengaged the fixed socket II the sult that the loading of the spring 15 is increased throughout retraction movement and is kept available to be expended in extension.

It should be noted that the spring I5 is under compression'between the blind and of the cap 9 and the plug lfijfixed within the pillar 3, and is therefore not affected by shock-absorbing and taxiingloads transmitted to th pillar. The resilient suspension ifor the tail wheel I1 is provided through a lever l8 which swings up and down about the pivot ill on the lower end bracket 20 forming the foot of a tubular sleeve 2| fitted in the pillar-3, The lever swings up and down under landing and taxiing loads against the resilient'resistance of the shock-absorber 22 secured-between the pin joint 23 in the sleeve 2| and the pin joint? on the lever l8.

Having regard to the fact that ,in the form shown the retractable unit is a tail-wheel, restrained castoring action is provided. The wheel is intended to be in trail of the pillar and the tubular sleeve 2| is rotatable under castoring infiuence, relative to the-pillarl and parts fast to the latter. To provide restraint to the castoring and also a self-centering'action, there are aligning cams, of which 25 is axially fixed but is rotatable with the sleeve 2|. The cam 25-co-operates with the cam 26 which is fixed relative to the pillar 3, and which is therefore non-rotatable, but the cam 26 is yieldabl axially against the infiuence of the spring 21. g

The unit may be securedin the retracted condition by jack pressure alone, in which case for extension it is necessary merely to open the jack line 6 to'relief, whereupon the energy stored in the compressed spring l5 causes peg In to ride up the cam slot and complete extensionoperation. No positive "up latch has been shown, but

as such latches are common in this art, any suitable latch may be provided for securing the unit in the retracted condition, if desired; such a latch will normally be manually actuated for release before re-extension can occur.

Whatlclaimis: g t

1. In a retractable aircraft undercarriage "or the like, a-pillar rotatable about a fixed pivot, a.

ground-engaging elementsupported from said pillar, a cap movable lengthwise of the pillar, cam means engageable by said cap, and s0 posi tioned relative to the retractional pivot as" to effect such movement of the capduring retraction and extension of the undercarriage, spring means reacting between the cap and the pillar to resist such movement during retraction, and to eflect such movement by reaction through the cam. during extension, and jack means to effect rotation of the pillar about the retractional pivot, in opposition to the spring means. 2. In a retractable aircraft undercarriage strut or the like, a pillar rotatable about a fixed pivot,

. to load the spring means, and cam means en gageableby the cap, and fixed, relative to the pivot 01' retraction, formed and arranged to ef-'" fect retraction of the strut by and during movement of the cap by the jack in the spring-loading sense, and to efi'ect extension of the strut by and during movement of the cap by the spring means in the opposite sense.

such approach of the second and third pivots, and consequent retraction of the assembly, and spring means resisting such retractional movement, and being loaded thereby to assist movement of the assembly in the opposite sense.

6. The combination of claim 5, wherein the cam is formed upon an involute curve about the first pivot. I

7. The combination of claim 5, wherein the cam is formed upon an involute curve about the first pivot, and with one terminal extending generally lengthwise of the pillar, to permit final extension of the cap along the pillar, and a lock carried by the cap for engagement with a complemental look by such final lengthwise movement, thereby to retain the assembly in extended 3. In a retractable aircraft undercarriage strut or the like, a pillar rotatable about afixed pivot, a cap movable lengthwise of the pillar, spring means resisting such movement of the cap in the retracting sense, and being thereby loaded toeifect such movement in the extendingsense, Jack means pivotally connected between a .pivot movable with the cap and a fixed pivot onset from the pivot of retraction, thepivot of retraction -and the two pivots of the jack thu constituting the apices of a deformable triangle, and a fixed cam operatively engaged by the cap, formed and arranged-to eflect retracting movement of the strut by and during deformation of the triangle byrthe Jack in the spring-loading sense, and to eifect extension of the strut by and during deformation of the triangle by the spring means intheoppositesense.j 7

A. In a retractable undercarriage strutor the like, a pillar rotatable about a fixed pivot, a cap movable lengthwise of the pillar, locking means carriedby the cap for engagement with complemental 10cm: means during the final exten siorial-movement ofthe cap, and releasabl by the first movement. ofthe capin the opposite sense, spring means resisting retractlonal movement of the c ip. and being thereby loaded to effect its extensional movement, Jack means pivotally connected between a pivot movable with the cap and a fixed pivot oil'set from the pivot of retraction, the three pivots thus constituting the apices of a deformable triangle, and a fixed cam operatively engaged by the cap, formed and arranged to effect, in sequence during deformation of the'triangle by the jack in the springloading sense, first release 01' said locking means,

and second retractionai'movement of the strut,

and to meet the reverse sequence by and during deformation ofthe triangle in the opposite sense by the spring means.

5. In a retractable undercarriage trut or the like, a pillar rotatable for retraction. and extension about a first pivot,a' cap.' guided-upon the pillar'ior movement lengthwise of the pillar a second pivot formed upon the'cap, a third pivot fixed relative to and oil'set from the first pivot, a camjand a cooperating cam follower, the one fixedly positioned and the other carried by the cap, formed and arranged to effect approach of the second and first pivots; and rotation of the whole assembly about the. first, pivot, upon. approach of the second and third pivots, and vice versa, Jack means operatively connected to eirect position.

, 8. In a retractable undercarriage strut or the' 3 I like, a pillar, a pivot about which the pillar is V rotatable for retraction and extension,-a memends being radially nearer said pivot than its other end, means interengaged between the pillar and said slidable member to efi'ect approach of the member towards the pivot of retraction, and

by reaction through the cam thereby to .eflect rotation of the assembly into retracted position, and resilient means loaded by such movement, for reaction to eflect reverse movement, throug the cam, in extending.

9. In a retractable aircraft undercarriage strut or the like, a pillar rotatable for retraction and f extension about a fixed pivot, a ground-engaging element supported from said pillar, a cap move abl lengthwise of the pillar, spring means reacting between the cap and pillar to urge them apart in all operative positions, cam means engageable by said cap, and so shaped and posi-H I tioned relative to the retractional pivot as to efiect retraction and accompanying continuing increase in the spring loading by approach of the cap andpillar, and by separation of the cap and pillar under the influence of the unloading spring means to eifect extension of the undercarriage strut, and jack means to eifect approach'of the cap and pillar in opposition to the spring means.

10. A retractable undercarriage strut as in claim 9, in which the pillar and cap telescopically interengage, and wherein the spring means is enclosed .thereby.

11. A retractable undercarriage strut as in claim 9, in which the spring means is initially loaded in compression. r

' 12. A retractable undercarriage strut as in claim 9, in which a lock element is formed upon the cap, and is arranged for engagement with a complemental lock element by the final extensional movement of the cap, and for disengagement by the initial approach movement of the cap, and wherein the cam means includes a first portion engageable by the cap throughout this portion of the caps movement, shaped to eflect only lock-releasing movement of the cap, and a second portion shaped to efiect only retractional 

